Watch crystal removing and replacing tool



52 54- i l I l I Jan. 22, 1963 E. c. HINRICHSEN ETAL 3,074,156

WATCH CRYSTAL REMOVING AND REPLACING TOOL Filed March 16, 1960 2 Sheets-Sheet 1 FIEI IN V EN TORS EJN R C, HlNRKLHSEN AND FRITZ A HARDEQ Jan. 22, 1963 E. c. HINRICHSEN ETAL ,0

WATCH CRYSTAL REMOVING AND REPLACING TOOL Filed March 16, 1960 2 Sheets-Sheet 2 FIG. 7

FEB

INVENTORS, EJNAR C.HINRICHSEN Am: BY FRITZ A. HARDER ATTO RME United States Patent C) The invention relates to tools for removing and replacing watch crystals, and is more particularly directed to a tool for use in connection with crystals made of plastic material or the like. The present application is a continuation-in-part of our application Serial No. 833,181, filed August 12, 1959 now abandoned.

In certain watch constructions it is desired to obtain access to the movement for repair or cleaning through the front face of the watch without removing the bezel. Various types of tools have been proposed to directly remove and replace crystals from the bezel without separating the bezel from the remainder of the watch. In prior art watch crystal removing and replacing tools, whether of the wrench, plier, or clamping sleeve type, the use of the tool has been restricted to a crystal of a particular size, or else a ring or other part of the tool has required replacement with another part to permit the tool to be used for operation upon a crystal of different size. Such prior art tools, when useful for different crystal sizes, are, in effect, a series of differently sized tools. Besides involving a large number of elements, they require proper selection and assembly by the watch repairman, with the attendant effort and loss of time.

An object of the invention is to provide a watch crystal removing and replacing tool which is simply, quickly and readily adjustable for operation upon practically all sizes of crystals without necessitating any change of the tools parts.

Another object of the invention is to provide a tool of the type under consideration which is simply, ruggedly and compactly constructed, particularly when the wide range of crystal sizes accommodated by the tool is considered.

A further object of the invention is to provide a watch crystal removing and replacing tool suitable for use in connection with practically all watch crystal sizes which, nevertheless, permits a crystal to be readily removed from and replaced in a watch without causing interference with the crown or other elements in the vicinity of the bezel.

Still another object of the invention is to provide a watch crystal removing and replacing tool which is most easily manipulated by the watch repairman, the tool only requiring positioning thereof with respect to the crystal, the turning of a thumb nut and simple lifting and downward motions, the tool securely maintaining its grip upon the crystal until the thumb nut is reversely turned to release and complete connection of the crystal to the bezel.

These, and other objects and advantages will be apparent from the following description of the preferred embodiment of the invention, taken in conjunction with the drawings, in which:

FIG. 1 is a side elevational view of the tool of the invention with the crystal-gripping fingers thereof in substantially fully retracted position;

FIG. 2 is a vertical sectional view of the tool in its retracted condition as shown in FIG. 1;

FIG. 3 is a view similar to FIG. 2, but showing the crystal-gripping fingers in substantially fully contracted position, or a position wherein the tool will grip a crystal of small size;

FIG. 4 is a view looking upwardly at the bottom of the tool in the condition thereof as shown in FIG. 1;

FIG. 5 is a view similar to FIG. 4, but showing the 3,74,l5 6 Patented Jan. 22, 1953 position of the fingers when the tool is in the contracted condition of FIG. 3;

FiG. 6 is an exploded, perspective view of the parts comprising the tool, except for the camming means coacting with the fingers to displace them in a diametral plane and the means for causing relative movement between the camming means and the fingers, this view further omitting the showing of a number of fingers for the purpose of clarity of illustration;

FIG. 7 is a top plan of a fixture suitable for holding a crystal of selected size preparatory to gripping by the tool and insertion of the crystal into a bezel; and

FIG. 8 is a side elevational view of the fixture shown in FIG. 7, this view however, also showing a crystal positioned in the fixture and gripped by the fingers of the tool, only several of which are partially shown.

Referring to FIGS. 1 to 6, the watch crystal removing and replacing tool of the invention generally comprises a base A upon which is mounted a plurality of individual fingers B on a diameter provided by the base. The fingers extend longitudinally from one side of the base in circumferentially spaced relationship, and have crystal-gripping portions 10 at their lower ends or the ends remote from the base. For cooperation with the fingers, camming means C is provided so that relative movement between the fingers and the camming means in a direction longitudinally or length wise of the fingers causes a uniform change in the diametral position of the crystal-gripping portions 10.

The fingers are provided with or engaged by resilient means D which acts to normally maintain the fingers crystal-gripping portions 10 in an outward or expanded position, and resists the displacement of the crystal-gripping portions toward a reduced diameter. When relative movement is provided between the fingers B and the camming means C in a direction longitudinally of the fingers against the force of the resilient means, the fingers and their crystal-gripping portions are collectively and nni formly displaced toward a position on a reduced diameter. Preferably, means E is provided for imparting relative movement between the fingers and the camming means, such means further and preferably serving to maintain a fixed relationship between the fingers and the camming means until changed by manual manipulation.

In greater detail, and referring particularly to FIGS. 2, 3 and 6, the base A comprises an annular disk 12 having a plurality of slots 14 extending radially inward from its periphery for a distance short of the disks central axis. The radial slots, which are equidistantly spaced from one another, may be any suitable number in excess of four, it being preferred to have 16 slots as shown on a disk having a relatively small diameter, for example, approximately 1%; inches. Inward of the peripheral edge of the disk, and on the top surface thereof, an annular groove 16 is provided, the continuity of the groove being broken by the intersecting slots. The base further comprises a washer 18 also provided with radial slot-s 19 extending through its thickness, these slots being equal in number and spacing to the slots 16 in the disk 12 so that when the disk and washer are placed face to face their slots may be aligned with one another. The disk and washer are provided with central apertures 20 and 20, respectively.

The fingers B are identical in shape and structure so that the following description of one finger is applicable to all of them. The fingers preferably are made of a rigid material such as brass. Each finger has a thickness slightly less than the width of a slot in the base. The finger is provided near its top end with an aperture 21 which extends through to the sides thereof. The portion of the finger projecting above the aperture is recessed at 22 to thereby provide an adjoining knob portion 24 3 at the top rear edge of the finger, such rear edge being designated 26.

Preferably, the fingers are each contoured to furnish a surface for coaction with the camming mean C to provide an increased measure of diametral displacement for the fingers crystal-gripping portions. This may be ac complishcd by forming the fingers of the contour illustrated. In profile, each of the fingers resembles the human thigh and leg permanently bent at the knee. The rear edge 26 is inclined at a rearwardly extending angle beginning at the point 27 approximately mid-way of the fingers length. The rear edge terminates at the fingers bottom edge 28, which it intersects at approximately a. right angle. The fingers bottom edge, together with the rear edge 26 and the front edge 30 are shaped to provide a lower portion having theappearance of a foot, which however is formed to provide a sharp toe or prong constituting the inwardly directed crystal-gripping portion 10.

The manner in which the fingers B are assembled with the base A will be evident from the showing of FIG. 6. A finger is inserted in each slot 14 of the disk 12 with the apertures 21 positioned above the top surface of the disk. The fingers are pivotally connected to the base by a wire ring 32. The ring is split so that an end 34 of the wire may be passed through the apertures before setting the wire, with the fingers thereon, in the groove 16. The ends of the wire ring are positioned intermediate a pair of slots to prevent a finger adjacent the wires ends from slipping through a slot. The groove 16 may be of a depth sufiicient to take the entire diameter of the pivot ring, or it may be semi-circular in cross-section, whereupon the cooperating washer 18 also is provided with a coacting semi-circular groove.

The radially slotted washer 18 is placed over the subassembly by aligning the slots thereof with the circumferentially spaced projecting portions of the fingers. The washer is of a thickness so that the top ends of the fingers extend above the top surface of the washer after assembly with the disk and fingers. A threaded stud or bolt 36 is then passed through the aligned apertures 21 20, with the slotted head of the bolt located on the underside of the disk 12. If desired, the underside of the disk may be countersunk to receive the head of the stud as shown. This assembly is completed by positioning a lock Washer 33 over the studs shank portion extending above the base washer 18, and the assembly is secured together by a nut 40 threaded onto the bolt and into engagement with the lock washer.

The resilient means D coacting with the fingers B is preferably in the form of an annular rubber ring 42. The resilient ring is of a diameter so that when it is placed around the upper ends of the fingers, in the recesses 22, the fingers are pivoted about the fulcrum provided by the pivot ring 32 so that the portions of the fingers below the fulcrum, including the crystal-gripping prongs 10, are normally maintained in a retracted or expanded posi tion. The described arrangement provides a substantial mechanical advantage in the respect that a relatively small measure of resilient force applied to the fingers by the resilient ring above the fulcrum results in a substantial force urging the fingers rearwardly against the camming means C as shown in FIG. 2.

The assembly of the tool is completed by positioning the camming means C in operative relationship with respect to the fingers. Preferably, the camming means is in the form of a cup or cylindrical sleeve 43 open at one end and provided at its opposite end with an inwardly directed, radial wall or flange 44. This wall is provided with a central aperture 46 through which the threaded shank of the stud 36 extends with a slight amount of clearance. In order to reduce wear of the fingers, where the sleeve engages the fingers, the inside diameter of the sleeve is provided with a chamfer 43 at the sleeves lower edge. The inside diameter of the sleeve is slightly greater than the. diameter of the base A.

The resilient force imposed upon the fingers by the annular resilient ring 42, together with the described contour of the fingers, serves to maintain the portions of the fingers below the fulcrum provided by the pivot ring 21 in engagement with the lower edge 43 of the sleeve, and with the base A in lowermost position as shown in FIG. 2, the fingers crystal-gripping portions 10 are retracted onto a comparatively large diameter. In fact, and as will be evident from FIG. 4, the described relationship of elements is such that the crystal-gripping portions are capable of retraction or location onto a diameter which is even greater than the diameter of the camming sleeve 43 which surrounds the base A. Thus, the described arrangement furnishes an unusually large range of adjustabiiity for the compact and relatively small size of the tool. The tool has a capacity to accommodate crystals as large as 21 ligne, as well as crystals as small as 6% ligne.

The means E for causing relative movement between the carnrning sleeve C and the fingers preferably comprises a thumb nut 50. The thumb nut preferably is threaded onto the stud 36, which extends above the camming sleeve, and is knurled to facilitate its turning. The described reaction or back pressure of the pivoted, resiliently mounted fingers upon the camming sleeve maintains the sleeve in engagement with the thumb nut. The thumb nut and sleeve may be provided with central bosses 52 and 54, respectively, to minimize friction between these two members when the thumb nut is rotated in engagement with the sleeve. To facilitate holding of the tool, the sleeve also may be knurled as shown in FIG. 1.

With the tool in the condition shown in FIGS. 1 and 2, the fingers may be rotated about the axis provided by the pivot ring 32 to move the fingers crystal-gripping portions it? to a reduced and crystal-gripping diameter by grasping the thumb nut 50 in one hand and the sleeve 43 in the other, and sliding the sleeve downwardly. It is preferred however, to rotate the thumb nut to provide the relative movement between the fingers and the camming sleeve, because after the crystal is so gripped, the tool does the holding, and the hands are not needed to maintain the grip on the crystal.

A fixture suitable for use in connection with the described tool and for a substantially full range of crystal sizes is shown in FIGS. 7 and 8. The fixture comprises a base plate 6t upon the upper surface of which is permanently mounted a jaw element 62. A second jaw element 64 is slidably mounted on the base plate for adjustment toward or away from the jaw 62. For this purpose, the adjustable jaw is provided with a central, longitudinally extending slot 66 through which extends a screw 68 fastened to the base plate 60. A knurled nut 70 is threaded onto the screw so that after the jaw 64 is moved to desired position to hold a plastic watch crystal, designated F, against the jaw 62, the nut 70 may be tightened to secure the jaw 64 in position. The bottom face of the plate 60 is provided with a layer of frictional material '72, which may take the form of corrugated rubber so that when the fixture is placed on a table or other surface, the fixture will not slide.

The tool operates in the following manner: With the crystal-gripping fingers substantially fully retracted, as shown in FIGS. 1 and 2, and with a crystal F of given size held in the fixture as shown in FIG. 8, the tool is placed over and surrounding the crystal. The thumb nut 50 is rotated to cause the base A, having the crystal-gripping fingers pivotally connected thereto, to be (drawn up into the sleeve 43. As the relative longitudinal movement between the fingers and the sleeve takes place, the edge 48 of the sleeve bearing against the rear inclined edges 26 of the fingers causes the fingers to be rotated about the fulcrum provided by the pivot ring 32 against the resilient force exerted by the annular rubber ring 42. As will be seen from a comparison between FIGS. 2 and 4, and 3 and 5', respectively, the crystal-gripping prongs collectively and uniformly are displaced toward a reduced di ameter. The fingers are buttressed at their rear edges where they engage the solid lower edge 48 of the camming sleeve. The sleeve in turn is maintained against the thumb nut 50 by the resilient pressure imposed by the fingers against the sleeve. The thumb nut is rotated until the prongs l0, collectively and uniformly press against the periphery of the crystal. The crystal being of plastic material and slightly flexible, it puffs or buckles at its center. The compressive force exerted by the many fingers around the periphery of the crystal reduces the crystals diameter slightly so that the crystal now held by the tool is easily lifted from between the jaws 62 and 64. The crystal now is securely held by the tool in readiness for insertion into a bezel, for the thumb nut 59 does not change position until manually rotated. The fingers maintain any selected position intermediate the substantially fully expanded position of FIGS. 1, 2, and 4, and the substantially fully contracted position of FIGS. 3 and 5.

The crystal, held by the tool, is then inserted into the bezel of a watch. The lower edges 28 of the crystalgripping fingers being angled, as shown, easily clear the crown or other appurtenant portions of the Watch which may otherwise interfere with setting the crystal in place. By rotating the thumb nut 50' in the opposite or fingerexpanding direction, the base and the fingers pivotally mounted thereon now move down and away from the top flange wall 44 of the sleeve, and the resilient force exerted by the rubber ring 42 causes the fingers to open and release the crystal. Upon the release of pressure by the gripping prongs upon the crystal, the crystal expands in circumference and snaps into position into the bezel.

In order to remove a crystal from the bezel of a watch, the tool is used in the same fashion as when gripping to remove the crystal from the fixture as above described.

It will be apparent that while a preferred embodiment of the invention has been described, various changes and modifications may be made Without :departing from the spirit and scope of the invention as sought to be defined in the following claims.

We claim:

1. A watch crystal removing and replacing tool comprising a base, a plurality of individual fingers mounted on a diameter provided by the base and extending longitudinally from one side of the base in circumferentially spaced relationship, said fingers terminating in inwardly directed crystal-gripping portions providing gripping edges for holding a plastic crystal, resilient means cooperable with the fingers resisting the displacement of the fingers toward a reduced diameter, and means cooperable with the fingers and movable with respect to the base against the force of said resilient means whereby the fingercooperable means causes a uniform displacement of the crystal-gripping portions toward a position on a reduced diameter, the compressive force exerted by the crystalgripping portions being sufficient to slightly reduce the lateral dimensions of a plastic crystal when the crystalgripping portions are displaced to crystal-holding position. 2. A watch crystal removing and replacing tool comprising a base, a plurality of individual fingers mounted on a diameter provided by the base and extending longitudinally from one side of the base in circumferentially spaced relationship, said fingers terminating in inwardly directed crystal-gripping portions providing gripping edges for holding a plastic crystal, resilient means cooperable with the fingers resisting the displacement of the fingers toward a reduced diameter, threaded means connected to the base and extending longitudinally from the opposite side thereof, means cooperable with the fingers and movable with respect to the base against the force of said resilient means whereby the finger-cooperable means causes a uniform displacement of the crystal-gripping portions towand a position on a reduced diameter, and means cooperable with said threaded means for imparting movement to said means cooperable with the fingers, the compressive force exerted by the crystal-gripping portions being sufficient to slightly reduce the diameter of a plastic crystal when the crystal-gripping portions are moved to crystal-holding position.

3. A watch crystal removing and replacing tool comprising a base, a plurality of individual fingers mounted on a diameter provided by the base and extending longitudinally from one side of the base in circumferentially spaced relationship, said fingers terminating in inwardly directed crystal-gripping portions providing gripping edges for holding a plastic crystal, resilient means cooperable with the fingers resisting the displacement of the fingers toward a reduced diameter, a threaded stud secured to the base and extending longitudinally from the opposite side thereof, means cooperable with the fingers and movable with respect to the base against the force of said resilient means whereby the finger-cooperable means causes a uniform displacement of the crystal-gripping portions toward a position on a reduced diameter, and a thumb nut cooperable with said threaded stud for imparting movement to said means cooperable with the fingers, the compressive force exerted by the crystalgripping portions being sufficient to slightly reduce the diameter of a plastic crystal when the crystal-gripping portions are moved to crystal-holding position.

4. A Watch crystal removing and replacing tool comprising a base, a plurality of individual fingers mounted on a diameter provided by the base and extending longitudinally from one side of the base in circumferentially spaced relationship, said fingers terminating in inwardly directed crystal-gripping portions providing gripping edges for holding a plastic crystal, resilient means cooperable with the fingers resisting the displacement of the fingers toward a reduced diameter, and a sleeve surrounding the base and in engagement with the fingers whereby relative movement between the fingers and the sleeve in a direction longitudinally of the fingers against the force of said resilient means causes a uniform displacement of the crystal-gripping portions toward a position on a reduced diameter, the compressive force exerted by the crystal-gripping portions being sufiicient to slightly reduce the diameter of a plastic crystal when the crystal-gripping portions are moved to crystal-holding position.

5. A watch crystal removing and replacing tool comprising a base, a plurality of individual fingers mounted on a diameter provided by the base and extending longitudinally from one side of the base in circumferentially spaced relationship, said fingers terminating in inwardly directed crystal-gripping portions providing gripping edges for holding a plastic crystal a central threaded stud connected to the base and extending longitudinally from the opposite side thereof, a sleeve surrounding the base and in engagement with the fingers for causing a uniform change in the diametral position of the crystal-gripping portions, said fingers being resiliently related to said sleeve to urge the fingers into engagement with the sleeve when the crystal-gripping portions are on a diameter greater than crystal-holding position, and means cooperable with said threaded stud for providing relative movement between said sleeve and said fingers in a direction longitudinally of the fingers, the compressive force exerted by the crystal-gripping portions being sufiicient to slightly reduce the diameter of a plastic crystal when the crystal-gripping portions are moved to crystal-holding position.

6. A watch crystal removing and replacing tool comprising a base, a plurality of individual fingers mounted on a diameter provided by the base and extending longitudinally from one side of the base in circumferentially spaced relationship, said fingers terminating in inwardly directed crystal-gripping portions providing gripping edges for holding a plastic crystal, resilient means cooperable with the fingers resisting the displacement of the fingers toward a reduced diameter, a threaded stud secured to the base and extending longitudinally from the opposite side thereof, a sleeve surrounding the base and in engagement with the fingers for causing uniform displacement of the crystal-gripping portions toward a position on a reduced diameter against the force of said resilient means, and a thumb nut cooperable with said threaded stud for providing relative movement between said sleeve and said fingers in a direction longitudinally of the fingers.

7. A watch crystal removing and replacing tool comprising an annular base, a plurality of individual fingers pivotally mounted on a diameter provided by the base and extending longitudinally from one side of the base in circumferentially spaced relationship, said fingers terminating in inwardly directed crystal-gripping portions providing gripping edges for holding a plastic crystal, a cylindrical sleeve surrounding the base and cooperable with the fingers, resilient means cooperable with the fingers resisting the displacement of the fingers toward a reduced diameter and normally maintaining a portion of each of said fingers on a diameter greater than the inside diameter of the sleeve, and means connected to the base for providing relative movement between the fingers and the sleeve in a direction longitudinally of the fingers to cause a uniform change in the diametric position of the crystal-gripping portions.

8. A watch crystal removing and replacing tool as set forth in claim 7, wherein the crystal-gripping portions are normally maintained on a diameter greater than the diameter of the base.

9. A watch crystal removing and replacing tool comprising an annular base, a plurality of individual fingers pivotally mounted on a diameter provided by the base and extending longitudinally from the lower side of the base in circumferentially spaced relationship, said fingers terminating in inwardly directed crystal-gripping portions providing gripping edges for holding a plastic crystal, a cylindrical sleeve closely surrounding the base and engageable with the fingers to cause their rotation about their pivotal connection to the base, resilient means c'ooperable with said fingers resisting the displacement of the fingers toward a reduced diameter and normally maintaining a portion of each of said fingers on a diameter greater than the inside diameter of the sleeve, a threaded stud connected to the base and extending longitudinally from the upper side thereof, and means cooperable with said threaded stud and cooperable with the sleeve for imparting longitudinal movement to said base and the fingers mounted thereon.

10. A watch crystal removing and replacing tool as set forth in claim 9, wherein the crystal-gripping portions are normally maintained on a diameter greater than the diameter of the base.

11. A watch crystal removing and replacing tool comprising an annular base, a plurality of individual, substantially rigid fingers pivotally mounted on a diameter provided by the base and extending longitudinally from the lower side of the base in circumferentially spaced relationship, said fingers having inwardly directed crystalgripping prongs at their lower ends, a cylindrical sleeve closely surrounding the base and engageable with the fingers to cause their rotation about their pivotal connection to the base, a resilient ring cooperable with said fingers resisting the collective displacement of the fingers toward a reduced diameter and normally maintaining a portion of each of said fingers on a diameter greater than the inside diameter of the sleeve at the lower end thereof, a central threaded stud secured to and extending longitudinally from the upper side of the base, and a thumb nut cooperable with said stud and in engagement with the sleeve for imparting longitudinal movement to said base and the fingers mounted thereon with respect to the sleeve.

12. A watch crystal removing and replacing tool as set forth in claim 11, wherein the crystal-gripping portions are normally maintained on a diameter greater than the diameter of the base.

7 13. A watch crystal removing and replacing tool comprising a base having circumferentially spaced, radial slots, fingers terminating in inwardly directed crystalgripping portions pivotally mounted in the slots, said crystal-gripping portions providing gripping edges for holding a plastic crystal, and means associated with the base to actuate the fingers to grip a crystal the compressive force exerted by the crystal-gripping portions being sufiicient to slightly reduce the lateral dimensions of a plastic crystal when the fingers are actuated to grip a crystal.

14. A watch crystal removing and replacing tool comprising an annular base having a plurality of circumferentially spaced, radial slots, respective, substantially rigid fingers positioned in each of said slots and pivotally connected to the base, said fingers having inwardly directed crystal-gripping prongs at their lower ends, a cylindrical sleeve closely surrounding the base and engageable with the fingers to cause their rotation about their pivotal connection to the base, resilient means cooperable with said fingers resisting the displacement of the fingers toward a reduced diameter and normally maintaining a portion of each of said fingers on a diameter greater than the inside diameter of the sleeve, threaded means connected to and extending longitudinally from the upper side of the base, and means cooperable with said threaded means and in engagement with the sleeve for imparting longitudinal movement to said base and the fingers mounted thereon with respect to the sleeve.

15. A watch crystal removing and replacing tool comprising an annular base having a plurality of circumferentially spaced, radial slots, respective, substantially rigid fingers positioned in each of said slots and pivotally connected to the base, said fingers having inwardly directed crystal-gripping prongs at their lower ends, a cylindrical sleeve closely surrounding the base and engageable with the fingers to cause their rotation about their pivotal connection to the base, an annular resilient ring cooperable with said fingers resisting the collective displacement of the fingers toward a reduced diameter and normally maintaining a portion of each of said fingers on a diameter greater than the inside diameter of the sleeve at the lower end thereof, a central threaded stud connected to and extending longitudinally from the upper side of the base, and a thumb nut cooperable with said stud and in engagement with the sleeve for imparting longitudinal movement to said base and the fingers mounted therein with respect to the sleeve.

16. A watch crystal removing and replacing tool as set forth in claim 15, wherein the fingers are each formed with a rear edge for engagement with the sleeve which is angled to provide an increased diameter for the portion of the finger below its connection to the base.

17, A watch crystal removing and replacing tool as set forth in claim 15, wherein the base comprises a slotted disk having an annular groove in the top surface thereof and a correspondingly slotted washer, said groove receiving a split ring extending through an aperture in each of the fingers to provide the pivotal connection of the fingers to the base, said disk, washer and split ring being secured by a nut threaded onto said threaded stud extending through said disk and washer.

18. A watch crystal removing and replacing tool comprising an annular base having a plurality of radially extending slots, individual, substantially rigid fingers respectively positioned in said slots and extending below the base, said fingers terminating in inwardly directed crystal gripping portions providing gripping edges for holding a plastic crystal, resilient means cooperable with said fingers for collectively urging said crystal gripping portions toward an expanded position, said resilient means being positioned adjacent the base on the upper side thereof and in engagement with the upper ends of the fingers, a threaded stud secured to the base and extending from the upper side thereof, annular fingerengaging means guided by said stud, and a thumb nut threaded on said stud for engagement with said finger engaging means.

19. A watch crystal removing and replacing tool comprising a base, a plurality of individual fingers mounted on a diameter provided by the base and extending longitudinally from one side of the base in circumferentially spaced relationship, said fingers terminating in inwardly directed crystal-gripping portions providing gripping edges for holding a plastic crystal, and means cooperable with the fingers whereby relative movement between said fingers and said means in a direction longitudinally of the fingers causes a uniform change in the diametral position of the crystal-gripping portions, said fingers being resiliently related to said means to urge the fingers into engagement with said means when the crystalgripping portions are on a diameter greater than crystalholding position, the compressive force exerted by the crystal-gripping portions being suificient to slightly reduce the lateral dimensions of a plastic crystal when the crystal-gripping portions are in crystal-holding position.

20. A watch crystal removing and replacing tool comprising a base, a plurality of individual fingers mounted on a diameter provided by the base and extending longitudinally from one side of the base in circumferentially spaced relationship, said fingers terminating in inwardly directed crystal-gripping portions providing gripping edges for holding a plastic crystal, threaded means connected to the base and extending longitudinally from the 0pposite side thereof, means cooperable with the fingers for causing a uniform change in the diametral position of the crystal-gripping portions, said fingers being resil iently related to said finger-cooperable means to urge the fingers into engagement with said means when the crystal-gripping portions are on a diameter greater than crystal-holding position, and means cooperable with said threaded means for providing relative movement between said fingers and said finger-cooperable means in a direction longitudinally of the fingers, the compressive force exerted by the crystal-gripping portions being sufficient to slightly reduce the lateral dimensions of a plastic crystal when the crystal-gripping portions are in crystal-holding position.

References Cited in the file of this patent UNITED STATES PATENTS 1,346,957 Hansen July 20, 1920 1,411,082 Gotsdanker Mar. 28, 1922 1,521,008 Clay Dec. 30, 1924 1,866,654 Kulp July 12, 1932 2,303,560 Knight Dec. 1, 1942 2,595,172 Schenke Apr. 29, 1952 2,613,561 Schwebel Oct. 14, 1952 FOREIGN PATENTS 246,302 Switzerland Sept. 1, 1947 

1. A WATCH CRYSTAL REMOVING AND REPLACING TOOL COMPRISING A BASE, A PLURALITY OF INDIVIDUAL FINGERS MOUNTED ON A DIAMETER PROVIDED BY THE BASE AND EXTENDING LONGITUDINALLY FROM ONE SIDE OF THE BASE IN CIRCUMFERENTIALLY SPACED RELATIONSHIP, SAID FINGERS TERMINATING IN INWARDLY DIRECTED CRYSTAL-GRIPPING PORTIONS PROVIDING GRIPPING EDGES FOR HOLDING A PLASTIC CRYSTAL, RESILIENT MEANS COOPERABLE WITH THE FINGERS RESISTING THE DISPLACEMENT OF THE FINGERS TOWARD A REDUCED DIAMETER, AND MEANS COOPERABLE WITH 